Can anyone suggest some ways to create BOKEH/shallow Depth of Field with the HDR-FX1?

[Bill Pryor]

"I just shot a short film using the FX1 and surprise, surprise, there was no way to get a shallow depth-of-field on this camera using standard video techniques.

Shooting as far tele as a could which equated to 60' from the actors to get the composition I wanted, the background trees and houses were still in fairly sharp focus. I used the widest aperture (f/2.2 - I think) and used neutral density filters to compensate for exposure. Still everything was in sharp focus. I just gave up on depth-of-field using this camera.

The JVC JY-H10U has nice depth-of-field (true 30p is nice too), but too much chroma noise to be usable for my application.

The best DOF on any camcorder (with an attached lens) is on Canon's Optura XI."
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I find those comments interesting. Depth of field is dependant on chip size, focal distance and aperture. If you zoom in but move 60 feet back to achieve a wider composition, you are not improving things at all. The closer the shot, the shallower the depth of field--zoom in to an ECU from 10 feet away and your background will soften.

There is no way a smaller chip camera can have a shallower depth of field under identical circumstances than a larger chip one.

Try this: get right up to the limit of your focal distance. If it is 6 inches, get 6" away from a small object. Zoom back to your widest angle. Focus on the object 6" away. Your depth of field will be really shallow. It's not how far or wide you're zoomed in; it's how far from the subject you are. Zooming in to a tighter shot, in effect, puts you closer to the subject. If you zoom in to a shot where you see the person's eyes and nose only, you probably will have a shallow depth of field if your aperture is wide enough. But if you set up a wider shot of the person, say from the waist up, by using a wide angle on your lens, your depth of field will be great. Go 60 feet away from the person and zoom to the same waist up shot, and your depth of field will be about the same.

It's not the format, it's not the brand of camera--the biggest contributing factor to shallow depth of field is the chip size, or negative size in the case of film. Chip size, aperture, focal distance from the subject, and distance of subject from the background--that's all you've got to work with.

[Barry Green]

Can't agree. The chip size is irrelevant to the actual depth of field of a shot. Depth of field is determined by the optics, the chip just records what the optics are giving it.

The chip size influences the field of view, not the depth of field. Smaller chips need wider lenses to deliver a usable field of view, larger chips can use more telephoto lenses to deliver that same field of view. The more telephoto you go, the shallower the DOF "look".

Now, Bill's correct in that two aspects of DOF theoretically cancel each other out, and those two aspects are distance-to-subject and focal length. The closer you get (and closer = shallower DOF), the wider-angle you have to be (and wider = deeper DOF). The farther away you get (and farther = deeper DOF) the more telephoto you have to use (and telephoto = shallower DOF). So in theory, you'd think that the two would cancel each other out.

However, in practice, it just isn't the case. Longer focal lengths lead to the APPEARANCE of shallower DOF. Here's a test shot that illustrates the difference:

http://www.icexpo.com/dvx100/DOF-Combined.jpg

In this shot, I framed up an object by going full wide-angle, and getting as close as I could. Then I shot the exact same framing by backing up and zooming in, until the frame is almost exactly the same. Then I split-screened it. Both shots were taken using the identical same aperture. As you can see, the telephoto version looks like it has a much softer background, the background looks a lot more out of focus.

The reason has to do with some optical trickery; technically the focus is probably the same on the background, but in the telephoto shot, due to the narrower field of view, a much smaller section of the background fills the entire frame. On the wide-angle shot you can see a lot more background, so the background is rendered smaller (which makes it look sharper). But on the telephoto shot only the central small portion of the background is used, and it's optically magnified to fill the frame. It is that magnification that makes the background appear to be more out of focus.

So -- to reiterate: for the shallow DOF look, the use of telephoto is crucial. The more telephoto you can get, the softer the background will appear to be. Equally important is aperture -- the wider the aperture, the softer the background.

You can go close instead -- going close narrows up the DOF considerably, but the wide-angle lens you need to use has detrimental effects on what you're trying to do. However, going close has a "secret weapon" -- most of these cameras we're using are capable of a wider aperture on wide-angle than they are on telephoto. At full wide-angle a DVX can go to f/1.6, whereas on full telephoto the most-open it can do is f/2.8. I believe the FX1/Z1 are the same. So if you go close, you can open the iris up a bit more, and get a comparable shallow-DOF look as could be obtained by backing up and zooming in (however, as stated earlier, the shot won't look the "same" -- the perspective exaggeration of the subject will be much more noticeable).

[Chris Leong]

And of course there's the original poster's original question - that of "bokeh", which refers to the aesthetic quality of the out-of-focus portions of the shot, and it usually applies to telephoto shots, portraits in particular.

Usually the term is (like the fine wines the word is derived from) used to refer to the qualities of particular makes, models and vintage of lenses.

Anything shot up close with a wide angle will tend to be distorted just due to camera-to-subject distance (perspective) and so any bokeh that may indeed exist is detracted from by the perspective distortion.

I think it's because we usually think of wide shots as being sharp all over, and of the tele shots as having more bokeh, that this thread was started in the first place.

I could, of course, be wrong, but I've been doing this since 1968, professionally since 1975, and so I don't think so.

Cheers
Chris

[John Jay]

Like so many Sony cameras the FX/Z has a hot spot as far as shallow DOF is concerned. As the focal length increases the maximum aperture decreases in size.

At approx 70% zoom the maximum aperture is F2.0 and this is the hot spot - if you need more Bokeh then put on a 1.4x telephoto converter whilst keeping the zoom at 70% then you will have even better DOF/Bokeh characteristic - pCAM says that a shave and haircut ECU has 5.5 inch DOF at 10 feet under this condition (f=54mm focal length including teleconverter @ F2.0)

BTW Bokeh gets better the more aperture blades there are (idealised perfect circle) and the FX/Z has 9 blades I seem to recall

In tight spaces such as indoors shooting through a mirror can help with pushing the background further away